In this study of the "impact" of substance use/abuse on job performance, it is planned with the full cooperation and support of management and the union to recruit as many subjects as possible from all classes of employees in 31 stores of a chain of supermarkets (N=2,922). (There is profit sharing by employees and a joint management-union operation of this chain, which enhances the chance of recruiting the employees as subjects). The main aims are: 1) To determine the degree of the relationship of substance use/abuse of supermarket employees to their work performance, as indicated by the degree to which substance use/abuse during a three months' period predicts to the change that occurs in job performance during that same three months' period; and 2) To develop data on the epidemiology (i.e., prevalence rates of various substances, frequencies of use, etc., and the problems associated with substance use/abuse) among employees of supermarkets (within the limitations of the degree to which the study sample represents all supermarket employees in the prescribed area). New behaviorally anchored rating scales (BARS) tailored to the specific employment situation are developed for the supervisors ratings of the employees' job performance.